A high-resolution tunneling magneto-resistance sensor interface circuit

2017 ◽  
Vol 31 (04) ◽  
pp. 1750030 ◽  
Author(s):  
Xiangyu Li ◽  
Liang Yin ◽  
Weiping Chen ◽  
Zhiqiang Gao ◽  
Xiaowei Liu
Keyword(s):  
Band Gap ◽  
Temperature Coefficient ◽  
Low Frequency ◽  
Low Noise ◽  
Instrumentation Amplifier ◽  
Interface Circuit ◽  
Input Noise ◽  
Rejection Ratio ◽  
Equivalent Input Noise ◽  
Magneto Resistance

In this paper, a chopper instrumentation amplifier and a high-precision and low-noise CMOS band gap reference in a standard 0.5 [Formula: see text] CMOS technology for a tunneling magneto-resistance (TMR) sensor is presented. The noise characteristic of TMR sensor is an important factor in determining the performance of the sensor. In order to obtain a larger signal to noise ratio (SNR), the analog front-end chip ASIC weak signal readout circuit of the sensor includes the chopper instrumentation amplifier; the high-precision and low-noise CMOS band gap reference. In order to achieve the low noise, the chopping technique is applied in the first stage amplifier. The low-frequency flicker noise is modulated to high-frequency by chopping switch, so that the modulator has a better noise suppression performance at the low frequency. The test results of interface circuit are shown as below: At a single 5 V supply, the power dissipation is 40 mW; the equivalent offset voltage is less than 10 uV; the equivalent input noise spectral density 30 nV/Hz[Formula: see text](@10 Hz), the equivalent input noise density of magnetic is 0.03 nTHz[Formula: see text](@10 Hz); the scale factor temperature coefficient is less than 10 ppm/[Formula: see text]C, the equivalent input offset temperature coefficient is less than 70 nV/[Formula: see text]C; the gain error is less than 0.05%, the common mode rejection ratio is greater than 120 dB, the power supply rejection ratio is greater than 115 dB; the nonlinear is 0.1% FS.

scholarly journals A Compact Low-Distortion Low-Power Instrumentation Amplifier

2010 ◽  
Vol 5 (1) ◽  
pp. 33-41
Author(s):  
Jader A. De Lima
Keyword(s):  
Low Frequency ◽  
Design Parameters ◽  
Instrumentation Amplifier ◽  
Cmos Process ◽  
Output Stage ◽  
Noise Spectral Density ◽  
Class Ab ◽  
Input Noise ◽  
Low Distortion ◽  
Equivalent Input Noise

A CMOS instrumentation amplifier based on a simple topology that comprises a double-input Gm-stage and a low-distortion class-AB output stage is presented. Sub-threshold design techniques are applied to attain high figures of differential-gain and rejection parameters. Analyses of input-referred noise and CMRR are comprehensively carried out and their dependence on design parameters determined. The prototype was fabricated in standard n-well CMOS process. For 5V-rail-to-rail supply and bias current of 100nA, stand-by consumption is only 16μW. Low-frequency parameters are ADM=86dB, CMRR=89.3dB, PSRR+=87dB, PSRR-=74dB. For a 6.5pF-damping capacitor, ΦM=73º and GBW=47KHz. The amplifier exhibits a THD of –64.5dB @100Hz for a 1Vpp-output swing. Input-noise spectral density is 5.2μV/ Hz @1Hz and 1.9μV/ Hz @10Hz, which gives an equivalent input-noise of 37.6μV, over 1Hz-200Hz bandwidth. This circuit may be employed for low-frequency, low-distortion signal processing, advantageously replacing the conventional 3-opamp approach for instrumentation amplifiers.

Study of a closed-loop high-precision front-end circuit for tunneling magneto-resistance sensors

2019 ◽  
Vol 33 (08) ◽  
pp. 1950085 ◽  
Author(s):  
Xiangyu Li ◽  
Jianping Hu ◽  
Xiaowei Liu
Keyword(s):  
High Precision ◽  
Closed Loop ◽  
Low Frequency ◽  
Cmos Technology ◽  
Low Noise ◽  
Corner Frequency ◽  
Cmos Process ◽  
Interface Circuit ◽  
Front End ◽  
Magneto Resistance

A closed-loop high-precision front-end interface circuit in a standard 0.35 [Formula: see text]m CMOS technology for a tunneling magneto-resistance (TMR) sensor is presented in this paper. In consideration of processing a low frequency and weak geomagnetic signal, a low-noise front-end detection circuit is proposed with chopper technique to eliminate the 1/f noise and offset of operational amplifier. A novel ripple suppression loop is proposed for eliminating the ripple in a tunneling magneto-resistance sensor interface circuit. Even harmonics is eliminated by fully differential structure. The interface is fabricated in a standard 0.35 [Formula: see text]m CMOS process and the active circuit area is about [Formula: see text]. The interface chip consumes 7 mW at a 5 V supply and the 1/f noise corner frequency is lower than 1 Hz. The interface circuit of TMR sensors can achieve a better noise level of [Formula: see text]. The ripple can be suppressed to less than 10 [Formula: see text]V by ripple suppression loop.

A low-noise transistorized seismic amplifier

1964 ◽  
Vol 54 (1) ◽  
pp. 347-368
Author(s):  
Stamatios N. Thanos
Keyword(s):  
High Reliability ◽  
Low Noise ◽  
Ocean Bottom ◽  
Low Frequencies ◽  
Input Noise ◽  
Remote Operation ◽  
Source Impedance ◽  
Ocean Bottom Seismographs ◽  
Equivalent Input Noise ◽  
Remote Calibration

abstract The use of transistors for the amplification of fractional microvolt signals at extremely low frequencies is illustrated in the design of an amplifier developed for use in a lunar seismograph. The amplifier has an equivalent input noise voltage of 0.2 microvolts, p-p, with a source impedance of 2000 ohms and a 3 db bandwidth of 0.035 cps to 22 cps. The nominal input impedance is 1700 ohms. It is completely transistorized and performs satisfactorily over a specified temperature range of −20°C to +100°C. Low power requirements, high reliability, and capability for remote calibration and gain change make this amplifier especially suitable for any field or remote operation under extreme environmental conditions. This amplifier is presently being used in ocean bottom seismographs and magnetic variometers.

A 790 nW Low-Noise Instrumentation Amplifier for Bio-Sensing Based On Gm-RSC Structure

2018 ◽  
Vol 27 (10) ◽  
pp. 1850157
Author(s):  
Tao Yin ◽  
Guocheng Huang ◽  
Xiaodong Xu ◽  
Yachao Zhang ◽  
Xinxia Cai ◽  
...  
Keyword(s):  
Low Power ◽  
Low Noise ◽  
Instrumentation Amplifier ◽  
Rejection Ratio ◽  
Power Supply Rejection Ratio ◽  
Transconductance Amplifier ◽  
Low Power Dissipation ◽  
Amplifier Stage ◽  
Potential Recording ◽  
Operational Frequency

This paper presents a low-power low-noise instrumentation amplifier (IA) for bio-potential recording. The proposed IA is based on a novel Gm-RSC structure, whose gain is determined by the transconductance (Gm) and the equivalent resistance ([Formula: see text]) of the switched-capacitor (SC) load. The transconductance amplifier stage is based on the current-reuse telescope topology to achieve low noise at low-power dissipation. A resistor-controlled oscillator is designed to generate desirable operational frequency for SC load and to continuously tune the mid-band gain of the IA for different biomedical applications. Measurement results show that the input referred noise of the proposed IA is about 1.27[Formula: see text][Formula: see text]VRMS ([Formula: see text][Formula: see text]Hz) and the noise efficiency factor is 3.3. The range of tunable gain is from 28 to 40[Formula: see text]dB. The common mode rejection ratio and power supply rejection ratio at 50[Formula: see text]Hz are 72 and 78[Formula: see text]dB, respectively. The IA consumes only 660[Formula: see text]nA current at 1.2[Formula: see text]V supply and the active area of the IA is only 0.035[Formula: see text]mm2.

Signal Detection Technology for Giant Magnetoresistance Sensors

2013 ◽  
Vol 303-306 ◽  
pp. 270-273 ◽  
Author(s):  
Jing Hua Hu ◽  
Meng Chun Pan ◽  
Wu Gang Tian ◽  
Jia Fei Hu
Keyword(s):  
Signal Processing ◽  
Signal Detection ◽  
Giant Magnetoresistance ◽  
Low Noise ◽  
Output Data ◽  
Input Noise ◽  
Algorithm Efficiency ◽  
Detection Technology ◽  
Equivalent Input Noise ◽  
Signal Processing Methods

Presently, many attentions have been paid on low-noise pre-amplifier circuits and steady signal processing methods, but seldom on the combination of two technologies. In this paper, a small size low noise pre-amplifier circuit with 110dB Common Mode Rejection Ratio（CMRR）has been developed for giant magnetoresistance sensors(GMR) and its equivalent input noise voltage density is about . In addition, we proposed a new signal processing method for the sensors. In the method, we defined the quotient between the complex multiplex computation times and the output data num as a new figure of merit to evaluate that algorithm efficiency in signal detection, and name that quotient the computation times -to- output data num ratio (CTOR). Simulation results showed that the new method realized better parameters evaluation precision and higher efficiency than Modified Rife method, could be implemented easily in embedded systems.

COMPARISON OF 1/f NOISE IN JFETs AND MOSFETs WITH SEVERAL FIGURES OF MERIT

2011 ◽  
Vol 10 (04) ◽  
pp. 447-465 ◽  
Author(s):  
FELIX A. LEVINZON ◽  
L. K. J. VANDAMME
Keyword(s):  
Thermal Noise ◽  
Empirical Relation ◽  
Low Noise ◽  
Corner Frequency ◽  
Current Gain ◽  
Noise Parameter ◽  
Input Noise ◽  
High Area ◽  
Measurement Results ◽  
Equivalent Input Noise

Measurement results are presented from 0.1 Hz to 100 kHz of 1/f and thermal noise in different n-JFETs, and n- and p-MOSFETs. The comparison of the 1/f noise is based on Hooge's empirical relation with the 1/f noise parameter α as figure of merit, without suggesting a physical origin. We find that the empirical relation for 1/f noise in MOSFETs and JFETs can be used as a tool to pinpoint the dominant noise source (either ΔN number fluctuations or Δμ mobility fluctuations) and its location, either in the channel or in the parasitic series resistance. Similar relations hold in JFETs and MOSFETs for the 1/f noise corner frequency fc, where thermal and 1/f noise are equal and the ratio fc/fT with fT the unity current gain frequency. The geometry independent parameter α and ratio fc/fT are compared from MOSFETs and JFETs with different channel width (W) and length (L). The results show that very low-noise n-JFETs have a corner frequency fc ≈ 40 Hz, and very low 1/f and thermal noise in agreement with the high W/L ratio and high area WL of the device. Specifically, the equivalent input noise voltage of the investigated JFET IF9030 was about 3.7 nV/√ Hz at 1 Hz, 1.3 nV/√Hz at 10 Hz, and about 0.6 nV/√ Hz (3.6 ×10-19 V2/Hz or Req th noise = 23 Ω) for f ≥ 100 Hz. The 1/f noise parameter α for that JFET is as low as α = 2 × 10-8. This α-value is among the lowest values ever observed. MOSFETs often have α, fc and fc/fT values that are a few decades higher than for JFETs.

An integrated low 1/f noise and high-sensitivity CMOS instrumentation amplifier for TMR sensors

2017 ◽  
Vol 31 (08) ◽  
pp. 1750070 ◽  
Author(s):  
Zhiqiang Gao ◽  
Bo Luan ◽  
Jincai Zhao ◽  
Xiaowei Liu
Keyword(s):  
Magnetic Tunnel Junction ◽  
High Sensitivity ◽  
Wheatstone Bridge ◽  
Instrumentation Amplifier ◽  
Noise Spectral Density ◽  
Input Noise ◽  
Magnetoresistive Sensor ◽  
Chip Scale Package ◽  
Equivalent Input Noise ◽  
Dc Current

In this paper, a very low 1/f noise integrated Wheatstone bridge magnetoresistive sensor ASIC based on magnetic tunnel junction (MTJ) technology is presented for high sensitivity measurements. The present CMOS instrumentation amplifier employs the gain-boost folded-cascode structure based on the capacitive-feedback chopper-stabilized technique. By chopping both the input and the output of the amplifier, combined with MTJ magnetoresistive sensitive elements, a noise equivalent magnetoresistance 1 nT/Hz[Formula: see text] at 2 Hz, the equivalent input noise spectral density 17 nV/Hz[Formula: see text](@2Hz) is achieved. The chip-scale package of the TMR sensor and the instrumentation amplifier is only about 5 mm × 5 mm × 1 mm, while the whole DC current dissipates only 2 mA.

scholarly journals A 76db 828nv/√Hz Low Noise Bio Signal OTA For Neural Signal Recording Applications

2018 ◽  
Vol 7 (3.3) ◽  
pp. 48
Author(s):  
Sarin Vijay Mythry ◽  
D Jackuline Moni
Keyword(s):  
Low Frequency ◽  
Low Noise ◽  
Cmos Process ◽  
Gain Bandwidth ◽  
Rejection Ratio ◽  
Power Supply Rejection Ratio ◽  
Research Article ◽  
Different Types ◽  
The Common ◽  
Low Amplitude

The low frequency, low amplitude biomedical signals which created a tremendous demand amongst clinicians and neuroscience researchers are to be amplified in the range of millihertz to kilohertz by rejecting the dc offsets. This research article presents a Bio Signal OTA (Bio-OTA) with 76dB gain, 828nV/ 16Hz"> noise and 390nW power is designed in 90nm CMOS process and also a brief survey on the different types of OTAs used for neuro recording applications is discussed. The Wilson current mirror is used to design 1volt Bio-OTA. The Common mode rejection ratio (CMRR) is obtained as 75dB, power supply rejection ratio (PSRR) is above 88dB and gain bandwidth product (GBW) is 223MHz.  

scholarly journals Over-the-Counter Hearing Aids: A Lost Decade for Change

2015 ◽  
Vol 2015 ◽  
pp. 1-15 ◽  
Author(s):  
Zoe Yee Ting Chan ◽  
Bradley McPherson
Keyword(s):  
Hearing Aids ◽  
Control Function ◽  
Low Cost ◽  
Low Frequency ◽  
Volume Control ◽  
Elderly Persons ◽  
Over The Counter ◽  
Input Noise ◽  
Irregular Frequency ◽  
Equivalent Input Noise

Background. Hearing aids sold directly to consumers in retail stores or through the internet, without individual prescription by audiological professionals, are termed over-the-counter (OTC) devices. This study aimed to determine whether there was any change in the electroacoustic characteristics of OTC devices compared to research carried out a decade earlier. The previous results indicated that most OTC devices were low-frequency-emphasis devices and were unsuitable for elderly people with presbycusis, who were likely to be the major consumers of these products.Methods. Ten OTC devices were selected and their electroacoustic performance was measured. Appropriate clients for the OTC devices were derived, using four linear prescription formulae, and OTC suitability for elderly persons with presbycusis was investigated.Results. OTC electroacoustic characteristics were similar to those in the earlier study. Most OTC devices were not acoustically appropriate for potential consumers with presbycusis. Although several of the devices could match prescriptive targets for individuals with presbycusis, their poor electroacoustic performance—including ineffective volume control function, high equivalent input noise, and irregular frequency response—may override their potential benefit.Conclusion. The low-cost OTC devices were generally not suitable for the main consumers of these products, and there has been little improvement in the appropriateness of these devices over the past decade.

scholarly journals Low Noise Interface ASIC of Micro Gyroscope with Ball-disc Rotor

Sensors ◽  
2020 ◽  
Vol 20 (4) ◽  
pp. 1238 ◽  
Author(s):  
Mingyuan Ren ◽  
Honghai Xu ◽  
Xiaowei Han ◽  
Changchun Dong ◽  
Xuebin Lu
Keyword(s):  
Noise Analysis ◽  
Cmos Technology ◽  
Low Noise ◽  
Circuit Analysis ◽  
Interface Circuit ◽  
Input Noise ◽  
Measurement Results ◽  
Noise Density

A low noise interface ASIC for micro gyroscope with ball-disc rotor is realized in 0.5µm CMOS technology. The interface circuit utilizes a transimpedance pre-amplifier which reduces input noise. The proposed interface achieves 0.003°/s/Hz1/2 noise density and 0.003°/s sensitivity with ±100°/s measure range. The functionality of the full circuit, including circuit analysis, noise analysis and measurement results, has been demonstrated.

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